There are three ways to de-seed tomatoes, depending on how perfect the remaining tomato needs to look.

1. If making a sauce, cut the tomatoes in half horizontally and squeeze out the seeds.
2. If making a dish that requires the tomato flesh to be chopped later, cut the tomatoes in half horizontally and scoop out the seeds using a teaspoon.
3. If making a dish where the de-seeded tomatoes will be on display, cut the tomatoes in half vertically, cut them in half again (into quarters), then carefully cut out the seeds and core using a sharp knife.